Universal electric furnace, combined with means for condensing zinc.



J. THOMSON. UNIVERSAL ELECTRIC FURNACE COMBINED WITH MEANS FOR 00APPLICATION FILED JUNE 7, 1913. 1,090,429. Patented Mar. 17, 1914.

'1 SHEETfl-SHEET 2.

NDENSING ZINC.

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WIT/ E8858 INVEN 0H J. THOMSON. UNIVERSAL ELECTRIC FURNACE COMBINED WITHMEANS FOR CONDENSING ZINC.

APPLICATION FILED JUNE 7, 1913.

1,090,429. Patented Mar. 17, 1914.

4 SHEETS-SHEET a.

N Q Q I x Q '3 w h- L- L// In Q m 6% a i iii- L Q I g h N G Q 7 ii Eg @2olj WITNESSES u J. THOMSON.

UNIVERSAL ELECTRIC FURNACE COMBINED WITH MEANS FOR CONDENSING ZINC.

APPLICATION FILED JUNB7, 1913 1,090,429. Patented Mar. 17, 1914.

4 SHEETS-SHEET 4,

WITNESSES INVENTOR 5W Emmi/y W M i l 44% A2, 4 01mm.

, D; Fig. 4 is a top plan view from the left OHN THOMSON, OF NEW YORK,N. Y.

UNIVERSAL ELECTRIC FURNACE, COMBINED WITH MEANS FOR CONDENSING ZINC.

Specification of Letters Patent.

Patented Mar. 17, 1914.

Application filed June 7, 1913. Serial No. 772,219.

To all whom it may concern: I

Be it known that JOHN THOMSON, a. citizen of the United States, and aresident of the borough of'Manhattan of the city of New York, State ofNew York, have in-' 'coni-panying drawings which are representativeembodiments of the invention.

Figure 1 is a side elevation; Fig. 2 is a transverse center section, forinstance, such a section as is taken on the plane which includes line A;Fig. 3 is a longitudinal center section taken along the line B, exceptthat the lower right hand quarter is viewed from the vertical planesindicated by lines C or hand of its transverse center line, but is ahorizontal section from the right hand side of said line, taken alongthe plane E; Fig. 5-

is a partial horizontal section of a sumpplug, showing a modification;Fig. 6 1s a cross sectional view of the resistor, as siich might appearif drawn into Fig. 2; and

Figs. 7 and 8 represent respectively a half cross section and partialside elevation of the aforesaid resistor when its sides, contiguous tothe charge, are sheathed.

As shown in the drawings, this adaptation of the furnace isvparticularly intended for the reduction of igneous oxidof zinc combinedwith carbon, when the inert residual of the reaction is of small amountand of an ashy or sintery character; for various sulfid or oxidized zincor lead-Zinc ores having a considerable content of gangue of suchcharacter as is capable of being fluidized, and it may also be readilymodified for general ore-smelting or the fusion of metals.

To avoid explanatory statements which would in fact be in the nature ofrepetitions, it is stated that this application=is more or lesscorrelated with several pending applications filed by the presentapplicant on January 2nd, 1913, and application bearing Serial No.739,795, which was filed on said date, is particularly cited. Thisapplication is also related to my applications bearing Serial Nos,760,915 and 760,916,filed April 14th, 1913, and Serial "No. 766,248,filed May 8th, 1913.

First confining the description to the drawings as they appear, thedecomposition of the charge is effected by heat derived by directconduction or radiation orby both, preferably from an electricallyincited porous bed-resistor, such as is ordinarily formed from pieces ofbroken carbonf The longitudinally extending resistor, as H, isinterpolated between carbon terminals, as 8, 8, provided with metallicelectrodes 9, 9, the energizing circuit being denoted by I. In crosssection it preferably simulates the form of a trapezoid, or in itsentirety a rectangular prismoid whose base rests upon a grating which,as here shown, is constituted of a series of spaced rods, as 10,-spanning a longitudinal throat 12. 'Along the horizontal zone of thefurnace occupied by the resistor there are no side walls, but housingsor abutments, as 13, .13, are provided at the ends of the furnace forincasing the terminals. A series of vertically buttransversely extendingrefractory plates, as 14, 14, of a material non-conductive toelectr'icity, are set along and at right angles to the sides of theresistor, in such manner that at least the inner .edgesthereof, 15, 15,correspond with the angles of said resistor. The stability of theseplates is insured by embedding theirlower ends in the sloped tampedplating or floor, as 515, which slopes inwardly and downwardly "towardthe resistor and by interlocking bricks above, as 1.

In the base of the furnace beneath the overhead hamper orcharge-receiving space 11181; described, are a series of lateralcondensing chambers, as J, which maybe more.

as 20, terminating in run-ofi' spouts, as

21, 21". These sluices 20, 20, are shown as 1 being located in thechamber, adjacent to the sidewalls of the condenser.

Between the inner edges 22', 22' of the septas23, 23, which form thecondensing chambers, adequate space is provided .for a sump 23. a Thissump extends along andas near to thegrating as is possible, but is farenough below the grating to leave spaces of suificient area, as 24, 24through which the fvolatilized roducts of the reaction may freely flowaterally into the parallel side chambers 25, 25, from whence. thecondensers are supplied. This sump is tamped in place upon tiles orbricks, as 26, supportedby a series of spaced pillars or blocks as27,preferably set to form a longitudina channe or flue, as 28, andseveral transverse ports, {IS-29; the latter servin to connect theaforesaid central flue and t 'e aforesaid parallel side chambers. Beforeforming the sump" a generous layer of -some unbound lubricant, sayartificial or natural flake graphite or carborundum sand, 8.8130 isspread upon the upper surfaces of the br cks 26; The s outs of the sumpare provided with suitab e ta plugs, as 27, 27; a f

By forming t e resistor with s lo sides greater stability isobtained;thef'f ine and gas which enter itflo'w from top bottom in a generalhorizontal direction thencede fiect and traverse downwardly throughdifferent vertical zones and, when-the reaction I so consumes the chargeas to formslope-like hollows, a531,, Fig. 6, avitation of its particleswill produce direct impingement upon-the resistor,-as indicated by thearrows a. By eliminating the side walls-along the'charg'e receivingspace, the main upper portion of the furnace virtually becomes simply anopen top or table,'and when the charge is in place thereon the sides andtop of the resistor are thereby completely inclosed or buried, asdenoted by the .broken lines 32, {52". i a

The functions of the lates 14,1!1, are manifold, for example, t ey serveto avoid a direct or longitudinal flow of electricity through thecharge; to support' the bricks .17, whereby to prevent charge materialfrom directly resting upon the apex of the resistor; as thrust membersbetween the end housings, and also enable the operator to readilyinclose one e e fl ll f the tween any pair of the plates. On the otherhand, there ma be instances when the said plates can be dispensed with.

When the charge is composed of igneous oxid of zinc and carbon (ZnO-l-C)whose residue is usually of nominal amount, ashy, clinkery or sintery incharacter, this can be readily, withdrawn from along any portion of thetable Again, the charge material may be backed with free bricks oritcanbe somewhat tamped from behind to maintain intimate contact withthe resistor, if such a mode of operation is preferred.

By placing the sump under and in close juxtaposition to the broad baseof the prismoidal resistor, the residue if liquidized or 4 any liberatedmetal such as lead, is free to flow between the spaces of the grate-rodsand thence downwardly into the sump, where it is continuously subjectedboth to direct radiated heat and also to the heat conveyed by theflowing fume and gases, whose 1mpinging temperature will be nearly ifnot quite equal to that of the interior of the resistor from whence theyare derived. The above described slag-flow is denoted by arrows b andthat of the volatilized products by arrows c. The particular object ofelevating the sump above the bases of the condensing chambers andsupporting it on spaced pillars, also in providing the parallel spacesalong its sidesfis to efiect circulation of the fume and gases, asindica ted by arrows d, thus completely enveloping the structure withheat at a high temperature. As a consequence of this the entire surfaceof the sump without and within, except only as to the conduction of thelimited area of the supporting pillars, is subjected to a tem--perat-ure whichis practically as high and uniforml distributed as in theresistor itself. This is a feature of time importance in that theresidue is there y not chilled, as by downward conduction of itsheatinto the brick-work of the furnace, nor is there an excessive drainof radiated heat from the base of the resistor. In the construction ofthe sump it is importantto use material'imrvious to leakage of itscontents. There is available in the art suitable material havingcharacteristics which render it not subjectto destructive attack fromthe slagsof various ores or concentrates thereof. Usually such materialis more or less inert, having anegligible coefiicientof expansion or contraction, yet when a tamped structure is closely bound with thebrick-work of a furnace, which will ordinarily have a much higherrelative coefficient of expansion or i that each will slope downwardlyand outcontraction, the latter may act. to disrupt the former. Thisdilliculty is avoided by separating the ends of the sump from itsspouts. as 34, Fig. 3, and also employing the aforesaid unbound layer 30which is preferably of a lubricating material such as graphite. Theresult is that the bricks of the furnace may expand when heated andcontract. when cooled without imparting detrimental tensile orcompressive stresses to the sump.

As the collection of matter in the sump may proceed at various rates,variable according to the constituents and character of the charge, itis desirable to readily ascertain when the accumulation has reached sucha volume as needs be removed. To this end the inelosing end blocks orplugs are pierced or slotted to receive rods, as 3.3,and if formed ofcarbon or carborundum they may be left in place. The holes for theserods are located so as to readily determine about the maximum depth ofresidue desired, which by manual operation may be indicated by sounding.If, however, the character of the slag is such as to be somewhatconductive of electricity, as would be the case if oxid or sulfid ofiron were present, then two carbon rods 35, 35, Fig.5, set approximatelyparal-..

lel to each other, horizontally, may be employed whereby an indicativeelectric signal may be obtained when the rising bath 36 reaches the rodsand thereby closes the circnit as through the wires 37, 37.

The trapezoidal cross sectional form of resistor lends itselfmostreadily to adaptation for special purposes. Thus, as shown in Fig.6, the outer faces ma be formed by stacking pieces of carbon which arelar er than the core, thereby realizing stability. Also, as theelectrical resistance will be less alon the sides than through theinterior, the ow of current and consequent heat development will begreater along the reaction zones. The angle of the sides is somewhatimmaterial. That shown, 15, appears to be quite adequate for stabilityof structure and yet is not sutiicient to interfere with a free downwardprecipitation of the residue,

whether it be ashy or fluid.

In certain cases it may be preferable to prevent the charge from comm indirect contact with the resistor car on. The present design andconstruction is uniquely adaptable thereto, and a preferred mo e ofrealizing such a condition is shown in Figs. 7 and 8. Thus shallowrecesses, as 38, are formed in the lates in the sides nearest to theresistor and these recesses are adapted to receive a series ofhorizontally spaced strips or rods, as 39, of a material immune toreaction, such as recrystallized carborundum (SiC). These strips mayreadily be set so avardly, whereby liquid residue will not colthe stripsby arrow n, finally passing be-.

tween the grate-bars to the sump, as arrow 11. This structureforms infact a strong rigid cage into which, by removing the upper cover bricks17, the carbon may be freely inserted. Moreover, it is particularly welladapted for carrying out the process of volatilization of ZnO when notcombined with carbon to primarily react, that is to say, the oxid fumewould then pass into the resistor when reaction between the said fumeand the incandescent carbon ensues, producing Zn-l-CO. Consequently,according tothat method, resistor reaction carbon would require to berenewed from time to time. This can readily be done, the need of whichwould be indicated by a change in or fluctua tion of the normal circuitvoltage..

\Vhile the accompanying drawings generally represent a. reduction fromworking lans, various shifts and modifications may e madewithout'evasion of the fundamental features of this design. For example,the rectangular prismoidal form of resistor may be compounded to operatein parallel or in series, and if the furnace were to be used for smeltlnother than zinkiferous orcs or for the fusion of metals, the sump mightthen be built directly in the throat while the spaces beneath and atthesides thereof may be heated either by fuel or a. separate electricresistor. Again, in support of the title of universal ap licability, itwould only be necessary to ma e a few changes in a furnace constructedaccording to the accompanying drawings to adapt it for, say, smeltmgcopper o r"lead ores or to fuse metals such as brass or aluminum. Forexample, if the charge and the reacting or meltlng effects are such thatmetallic fume is not produced, then the resistor may be sheathed withthin SiC plates without providing them with perforations or slots,and'by filling the condensing chambers, as with ood non-conductingbricks, the sump won (1 for several purposes be kept adequately hot. Onthe other hand the space 28 beneath the sump ma be packed with brokencarbon to connect with carbon terminals set in the ends of the furnace.In this wise there would still be provision for a comparatively fullcirculation of fume or gases through the broken carbon, while, if reuired, additional heat could be intermittent y or continuously impartedto the sump and its surroundings by electrically energizing what mightthen be termed the sump-resistor. In conclusion it can be conservativelystated that a high thermal efficiency may be realized by the use of thisfurnace when employed fer the vari ous urposes herein mentioned.

.W iat I claim is:

1. In an electric furnace, a resistor whose transverse form istrapezoidal, a supporting grating therefor and an underlying sum 2. Inan electric furnace, a resistor w ose transverse form is trapezoidal,the reacting smelting or melting efi'cct taking lace alon or contiguousto a sloped side or 0th slopes sides thereof. i

3. An electric zinc furnace having supported on a grate a longitudinallyextending resistor of trapezoidal cross section and a charge receivingfloor which slopes downwardl toward the grate.

4. in electric furnace having an open table, a resistor reposingthereon, abutments containing the terminals and an underlying sump. Y

5. An electric furnace having an open table, a longitudinall extendingresistor reposing thereon, a pliirality of vertically and transverselyextending spaced plates resting upon the table, abutments contain ingtheterminals and an underlying sump.

6. An electric furnace having a longitudinully extending carbon resistorwhose transverse form is trapezoidal, the sloped sides thereof beingprotected with a refractory plating of material having a lesserelectrical conductivity than the interposed. carbon.

7. In an electric zinc furnace, a orous carbon resistor having a surfacet ereof, which emits heat to the charge, plated with perforated orslotted refractory material immune to tlu; reaction, the fume and gaspassing through spaces in the lating, thence into the said resistor andfinally to a condenser.

8. In an electric furnace, a tamped receiving sump, disposed beneath aresistor, which said sump 15 supported u on pillars s arranged as toprovide 8.3311113 ity of free spaces under its bottom an along itssides.

'9. In an electric furnace, atamped receiving sump, whose ends aresevered from tho spouts and whose bottom is separated from thebrick-work by a layer of unbound lubricatingmaterial.

10. In an electric furnace, a receivin sump having end inclosing blocksprovide with refractory rods-for-aseertainiy when the sump-charge shouldbe met V 11. An electric zinc furnace comprising a resistor, asupporting therefor, l

throat beneath the gratin a sump beneath the throat, spaces surroun ingthe sump into which the volatilized products of the reaction mustprimarily flow audfrom whence the condensing system is supplied.

12. In an electric zinc furnace, a porous carbon resistor, a gratingupon which the resistor rests, an underlying sump into and toward whichthe inert and volatile products of the reaction (low, side spacesparalleling the sum into which only fume and gas are deflected and asystem of condensing chambers which receive the fume flowing from saidspaces.

13. In an electric zinc furnace, a porous carbon resistor whosetransverse form is trapezoidal, its base resting upon a grating beneathwhich is a condensing system, the reaction proceeding at or contiguousto the slopes from whence the volatilized )roducts enter the resistor inhorizontal directions theuafter deflecting and passing down to thegrating in a plurality of distinct vertical zones.

14. In an electric zinc furnace, a resistor whose transverse form istrapezoidal, its base restin upon a grating beneath which is a sump, 51creaction proceeding at or contiguous to the slopes from whence the inertor metallic products. if fluidized, flow down along the outer surfacesof said slopes, dellect through spaces in the grating and fall into thesump.

15. An electric furnace having a resistor trapezoidal in cross section,a chargereceiving floor sloping downwardly and in wardly along each sideof the resistor, and a longitudinally -extending sump below the adjacentends of the floor. 2.

16. .-\combined electricfurn'ace and fume condenser-having alongitudinally-extending resistor. an open charge-receiving table havingend walls but no side walls that extend above the supportim surface ofthe table, the table being provided with a grating upon which theresistor rests, a sump under the grating, and longitudinally-extendingcondensing chambers arranged upon opposite sides of the sump below thetable and having therein sluices adjacent to the outer side walls of thecondenser for receiving the liquid metal. i

17. In a combined ziucfurnace and condenser, a resistor supported upon agrate of a char e-receiving table, a sump located I below the resistor,and a condensing system arranged below said table, the floor of thecharge-receiving table slopin downwardly .and inwardly toward theresistor, the condensing system having floor portions sloping downwardlyand outwarg y so that t e condensed liquid metal can ow into a receivingsluice arranged along a side of the interior of the condenser.

18. In a condensing system, a. centrallyarrangedlongitudinally-extending sump, and condensing chambers arranged :at thesides of said sump, the sump being supported on spaced pillars or'blocks to provide a free passageway between the chambers both above andbelow the sump, the sump also being arranged so that the ,fumes enteringthe condensing system can flow downwardly past both sides of the sump.

This specification signed and witnessed this 4th day of May, 1913.

' JOHN THOMSON; Signed in the presence of JCHN REID AGNEW, FERDINAND A.KUBLEB.

